Carburetor



June 12, 1956 s. M. UDALE 2,750,171

CARBURETOR Filed Nov. 2, 1953 IN V EN TOR.

CARBURETOR Stanley M. Udale, Detroit, Mich., assignor to Holley Carburetor Company, Detroit, Mich., a corporation of Michigan Application November 2, 1953, Serial No. 389,647

4 Claims. (Cl. 261--59)v The object of this invention is to supply fuel toa carburetor without the use of any fuel pump. So far, all attempts at self-feed or sucker carburetors failed; although a large fortune was spent in developing them. For one reason or another, freezing of the air valve-costfailure on long hillsthey all failed. None ever failed because of vapor lock. Of that they were free; hence, 111e idea never altogether died, as vapor lock continues to be a serious problem as fuels get more volatile and the weather gets warmer.

If an anterior throttle is used, this system fails at wide open throttle low engine speeds. If the ordinary throttle is used, an obsolete air valve in the air entrance must be used and air valve carburetors are viewed unfavorably as very obsolete in 1953.

If the throttle is automatically regulated there is then a new dea for sucker type carburetors. If the throttle is positively closed and opened permissibly, then at wide open throttle low engine speed, the suction does not fall below a predetermined minimum. Of course, this may mean a slight increase in compression or a slight decrease in octane rating, but such slight changes are not too important; in fact, the lower octane may be money in the bank. Actually these sucker type carburetors did fail to give the feel of rapid acceleration, but the actual acceleration as measured in seconds and tenths of a second was almost equal to that of an ordinary plain tube carburetor equipped to work with an ordinary AC fuel pump. Of course, the suction downstream of the throttle lifted the fuel and as the speed increased, the throttle opened automatically. With heavy trucks no attempt is ever made to operate at lowest engine speedwide open throttle. Three, four and even more speed ratios are provided to get torque.

The figure shows diagrammatically the preferred form of my invention.

In the figure:

10 is the air entrance.

12 is a primary venturi therein.

14 is a secondary venturi therein.

16 is the throttle with a downstream portion marked A slightly greater than upstream portion marked B.

18 is the throttle shaft.

20 is the slotted lever.

22 is the throttle rod to positively close and to permit the throttle to open.

24 is the other end of lever 20.

26 is a diaphragm.

28 is a vacuum chamber.

30 is a spring inside 28.

32 is a horizontal tube and acts as a passage from the throat of secondary venturi 14 and chamber 28.

34 is the float chamber vented through tube 64 to inlet manifold suction. 36 is the fuel line from 38 which is the fuel tank vented to the atmosphere at 60.

40 is the fuel inlet valve leading into the float chamber nited States Patent 42 is the fuel passage from chamber 34 to nozzle struc ture 44 made of a streamlined shape.

46 is the metered air for idle.

48 is the air nozzle.

50 is one of many fuel outlets delivering fuel to the throat of the third venturi formed around the streamlined nozzle 44.

52 is the fuel metering needle which moves.

54 is the fuel metering needle diaphragm.

56 is an ordinary vacuum operated power economizer spring. (It insures power at wide open and, under throttle, it insures economy.)

58 is the spring support, but usually this is adjusted by a spring (omitted for the sake of clarity).

An outlet manifold 62 takes the fuel and air from nozzle 44 in a well-known manner.

To start-a lever 70 controls a valve 69 so as to admit atmospheric air from passage 68. Lever 74 is pivoted at 72 and connected through a rod 77 to diaphragm 26. A slot 76 in the left-hand end of lever 74 engages with a pin in the lower end 24 of slotted link 20.

Operation With valve 69 open, atmospheric pressure acts on the float chamber 34 which must be large enough to start the engine. The moment the engine starts, valve 69 is closed (as shown).

The engine picks up speed. The diaphragm 26 rises; lever 74 is rotated anti-clockwise; lever 20 is also rotated anti-clockwise, tending to open throttle 16 anti-clockwise. Obviously a shift to the right of pivot 72 will increase the rate of opening of throttle 16. Throttle 16 is permitted to open by the link 22 and is assisted in opening by the fact that the distance A is greater than B in throttle 16.

The fuel-air ratio is controlled by the diaphragm 54 and metering needle valve 52 so that at low loads and high speed economy (16:1 mixture) is obtained, and at wide open throttle maximum loads the minimum suction prevails and the metering needle valve 52 rises and a relatively rich (14:1) mixture is available.

The valve 47 regulates the low speed air for idling.

What I claim is:

1. In an anterior throttle type carburetor an air entrance, a venturi therein, an air outlet, a suction opened positively closed permissive throttle therein located downstream of said venturi, a fuel nozzle downstream of said throttle, a venturi into which said nozzle discharges, a float chamber vented to the air pressure below the air throttle, a fuel passage leading to said nozzle from said float chamber, a throttle rod, a one-way connection therefor, a throttle lever incorporating the one-way connection and positively connected to said throttle so that the throttle is positively closed and is opened permissibly, a diaphragm, an air chamber, said diaphragm forming one wall of said chamber, a passage from the chamber to the throat of the first mentioned air venturi, a spring engaging the diaphragm, a link from the diaphragm, a second throttle lever positively connected to said throttle and to said link so as to open said throttle in response to suction in the throat of said first mentioned air venturi.

2. In a device as set forth in claim 1, a second diaphragm, second spring means engaging said second diaphragm, a needle metering fuel valve connected to said second diaphragm and located so as to control the fuel flow through said fuel passage connecting said float chamber to said nozzle, means for subjecting said second diaphragm to the suction in said float chamber so as to reduce fuel flow at high suctions.

3. In an anterior throttle type carburetor, an air entrance, a venturi therein, an air outlet, a suction opened positively closed permissive throttle therein located downstream, of said venturi, a fuel nozzle downstream of said throttle, a venturi into which said nozzle discharges, a float chamber vented to the air pressure below the air throttle, a fuel passage leading to said nozzle from said fioat chamber, a, throttle rod, a one-way connectionv therefor, a throttle lever incorporating the one-way connection and positively connected to said throttle so that the throttle is positively closed and is opened permissibly, a diaphragm, an air chamber, said diaphragm forming one wall of said chamber, a passage from the chamber to. the throat of the first mentioned air venturi, a spring engaging the diaphragm, a link from the diaphragm, a second throttle lever positively connected, to said throttle. and to said link so as to open said throttle in response, to suction in the throat of said first mentioned air venturi, the throttle being of the butterfly type and being made with the downstream lip longer than the upstream lip.

4. In a device as set forth in claim 1, a second diaphragm, second spring means engaging said second diaphragm, a needle metering fuel valve connected to said second diaphragm and located so as to control the fuel flow through said fuel passage connecting said float chamber to said nozzle, the throttle being of the butterfly type and being made Wit-h the downstream lip longer than the upstream lip, means for subjecting said second diaphragm to the suction in said float chamber so as to reduce fuel flow at high suctions.

References Cited in the file of this patent UNITED STATES PATENTS 

